code: def common_step(self, batch: Batch) -> Tuple[Tensor, Tensor]:
      batch_size = batch["paper"].batch_size
      y_hat = self(batch.x_dict, batch.edge_index_dict)["paper"][
          :batch_size
      ]
      y = batch["paper"].y[:batch_size]
      return y_hat, y
  
imports: import os.path
  from typing import Dict, List, Tuple
  import pytorch_lightning
  import torch
  import torch.nn.functional
  from pytorch_lightning import LightningModule, Trainer
  from pytorch_lightning.callbacks import ModelCheckpoint
  from torch import Tensor
  from torchmetrics import Accuracy
  import torch_geometric.transforms
  from torch_geometric.data import Batch
  from torch_geometric.data.lightning import LightningNodeData
  from torch_geometric.datasets import OGB_MAG
  from torch_geometric.nn import Linear, SAGEConv, to_hetero
  from torch_geometric.typing import EdgeType, NodeType
label_desc: Use image node_id 3 for calling the RelationalGNN obj's underlying member method code with example usage: obj.common_step(batch) and returns: y_hat,  y